Jennifer Garner thinks sets where women are in charge are ''different''.

The '13 Going On 30' star says it can make a difference ''whoever is leading the charge'' on a movie and it is ''reflected in the way the ship is run''.

Speaking to the Time's Up CEO Lisa Borders at the 2019 Makers Conference, she said: ''To me, I've done two films with women, and a TV show driven by women and directed mostly by women, so I feel like oh is it a challenge? Oh yeah, no I'm down, I've got that. I didn't know that we had to announce it. I announce that I will take the 4 per cent challenge. And you know what, those sets are different. They are different ... Whoever is leading the charge it's reflected in the crew, it's reflected in the way the ship is run and just the difference kinds of conversations you have on set.''

The 4 per cent challenge aims to get more women into the film industry and encourage studios to hire more female directors and crew.

Jennifer has had a number of differing roles over the year but for her latest movie, she learned MMA, gun and knife skills to star as Riley in the action revenge movie 'Peppermint'.

Speaking about her training for the movie, she said: ''I've been training for a while on this. I did MMA skills, gun skills, knife skills. It was the connection to the physical that made me kind of understand her fight for her daughter.''